This application claims the priority of German application 198 06 520.5, filed Feb. 17, 1998, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a process for sterilizing, filling and sealing containers in a sterilization chamber, in which process
at least one container to be sterilized as well as a closing element arranged at the container is inserted into an opened sterilization chamber, PA1 the sterilization chamber is subsequently sealed gastight and evacuated. PA1 at least one gas to be ionized is fed into the sterilization chamber, in which a low-pressure plasma is ignited for a long enough time to effect sterilization, PA1 the sterilization chamber is subsequently put under a suitable pressure for the purpose of filling the container, PA1 the container is subsequently filled by means of a filling tube projecting into the sterilization chamber and then closed by means of the closing element, and PA1 the filled and closed container is finally removed from the reopened sterilization chamber. PA1 in addition to the container and the closing element, all surfaces of the filling tube projecting into the sterilization chamber as well as the inner walls of the sterilization chamber are sterilized, PA1 and, in order to generate the pressure necessary for the filling of the container, a sterile gas is fed into the sterilization chamber.
In a process of this type (U.S. Pat. No. 5,801,354), it is more incidentally disclosed that, after plasma sterilization, when normal pressure again prevails in the sterilization chamber, the container inside the sterilization chamber can be filled with a liquid. For this, a filling tube is inserted into the sterilization chamber, so that the container is sterilized, filled and sealed in the sterilization chamber. The publication gives no further details on this process. In particular it is not disclosed how the inner walls of the sterilization chamber are made sterile after the container has been placed inside the sterilization chamber, as the known publication lays emphasis on the fact that essentially only the inner surfaces of the containers are sterilized.
It is an object of the present invention to create the conditions whereby at least one container can actually be sterilized in a sterilization chamber by means of a low-pressure plasma, thereafter filled and subsequently closed.
This object has been achieved in accordance with the present invention in that
The present invention is based on consideration of the fact that after the sterilization chamber is opened in order to insert at least one container and its respective closing element, unsterile surrounding air gets into the sterilization chamber and thus the inner walls of the chamber and the surfaces of the filling tube projecting therein become unsterile.
In the case of the process according to the present invention, the necessary elements for igniting a low-pressure plasma, for example an induction coil or electrodes, are so arranged that, in addition to the container and the closing element, also all surfaces of the filling tube projecting into the sterilization chamber as well as the inner walls of the sterilization chamber are sterilized. As filling cannot take place when the vacuum necessary for sterilizing prevails, it is further taken into account that the ventilation of the sterilization chamber after the sterilization process also takes place in sterile conditions.
An inert gas can be used as a sterile gas, whereby a sterile filter may be provided at the connection to the sterilization chamber. The use of an oxygen-free gas is in any case purposeful, so that oxidation of the filling goods is avoided.
A slight low pressure, normal pressure or even a slight overpressure can be chosen for the filling of the container. A slight overpressure is advantageous in the case of a liquid containing carbon dioxide, as it prevents the liquid from foaming excessively.
In order to accelerate the process, filling of the container can begin before a suitable pressure has been achieved. The filling valve of the filling tube thus opens during ventilation of the sterilization chamber, after sterilization has taken place.
In order that separate devices for applying the closing elements to the sterilization chamber need not be provided, it is provided in a further embodiment of the process of the present invention that the container to be inserted is at first closed by means of the closing element but can be easily opened, and that the closing element of the closed container is removed after it has been inserted in the sterilization chamber in order to uncover the filling opening. This means that devices for handling the closing element in the sterilization chamber are necessary; however, additional transport devices, on the other hand, can be omitted.
In order that the filling tube does not hinder the devices for handling the closing elements, it is further provided that the filling tube can be swivelled from a filling position to an inactive position and back.
These and further objects, features and advantages of the present invention will become more readily apparent from the following detailed description thereof when taken in conjunction with the accompanying drawing.